<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>

    <script>
        var st1='10'
        console.log(parseInt(st1))
        console.log(parseInt('100'))
        let arr=['1','2','3']
        console.log(arr[2])
        //输出 获取指定值
        arr.push('4')
        console.log(arr)
        //push尾部增加元素
        arr.pop()
        console.log(arr)
        //pop移除数组最后一个元素
        arr.shift()
        console.log(arr)
        //shift移除头部和返回第一个元素
        let arrs=[1,2,3,4,5]
        arrs.splice(2,0,'a','b','c')
        console.log(arrs)
        //新增
        arrs.splice(3,2)
        console.log(arrs)    
        //删除
        arrs.splice(1,2,'E','F')
        console.log(arrs)
        //修改
    </script>
</body>
</html>